Jupiter Chorus

Jupiter Chorus

Jovian chorus is generated in Jupiter's radiation belts by
electrons spiraling along Jupiter's magnetic field lines in
this region. Once generated, the chorus waves interact with
the moving electrons, disturbing the spiral orbit of the
electrons and causing them to fall into the Jupiter's ionosphere
along the magnetic field lines at high latitudes.

Chorus waves consist of a rapid succession of intense
ascending tones, rising in frequency over very short time
intervals, each tone lasting typically less than one second.
The frequencies of these rising tones occur in the audio
frequency range and sound like a dawn chorus of chirping birds,
a sound which gives these waves their name.

These signals were recorded by the Voyager 1 plasma wave instrument
during the flyby of Jupiter on March 5, 1979. Low frequency noise
has been filtered out and the recorded signals have been slowed down
by a factor of 4 in order to shift the frequency down to make the
chorus signals easier to hear. The labels on the spectrogram provide
the actual values of time along the horizontal axis and frequency along
the vertical axis. The intensity is color-coded with weak signals
blue and strong signals red.